Mechanism Study Of Interfacial Oxygen Vacancies Confinement Activate Peroxymonosulfate To Orientation Generate Singlet Oxygen

With the rapid development of our country’s economic construction and the rapid improvement of medical level,the environmental pollution caused by the massive use of antibiotics in medical wastewater is becoming more and more serious.However,conventional wastewater treatment process is difficult to effectively remove these organic wastewater with complex composition,so new treatment methods represented by advanced oxidation technology of semiconductor photocatalysis and advanced oxidation technology of persulfate are being widely studied.Although the advanced persulfate oxidation technology,which generates·SO₄^-degrades pollutants by activating peroxymonosulfate（PMS）,has a strong oxidation capacity,PMS is prone to uncontrollable decomposition under light conditions which will greatly reduce the utilization of persulfate.Therefore,the combination of semiconductor photocatalytic advanced oxidation technology and persulfate advanced oxidation technology was chosen.For heterojunction photocatalysts,the difference in the work function of their components leads to the directional transfer of photogenerated electrons to components with larger work functions,and the interfacial oxygen vacancies act as electron transport channels in this process.This limits the electron migration process to a small area near the interface oxygen vacancy,so the probability of photogenerated electrons encountering the PMS molecules adsorbed by the interface oxygen vacancy during the migration process is greatly increased.The ~1O₂ generation path in the photocatalytic reaction is regulated by activating PMS,so that more ~1O₂ is generated in the reaction system to attack organic pollutants with benzene ring,and then the reaction intermediates can be effectively degraded and removed by active radicals such as·OH and·O₂^-.Therefore,in this paper,oxides semiconductor represented by BiOCl and ZnO were selected to construct heterojunctions with metals Bi and Cu₉S₅.The specific research content is summarized as follows:1.Bi/BiO_1-xCl heterojunction with the best interfacial oxygen vacancy concentration was successfully prepared by microwave-assisted synthesis.In the reaction system with 2.5 mg PMS and visible light,the catalyst could degrade 5 mg·L^-1 carbamazepine by more than 70%in 180 min.The characterization and experimental results show that bismuth simple as a semi-metal,can produce local surface plasmon resonance effect under light,which can enhance the utilization efficiency of the material to visible light.The interfacial electric field formed by the Bi/BiO_1-xCl heterojunction can greatly improve the spatial separation efficiency of photogenerated carriers.Finally,Bi/BiO_1-xCl ohmic junction heterojunction with appropriate concentration of interfacial oxygen vacancy was obtained.Under the action of interfacial oxygen vacancy domain,a large number of photogenerated electrons were continuously transferred to the adsorption-protected PMS,thus regulating the PMS decomposition pathway to generate a large amount of ~1O₂ for the degradation of carbamazepine.2.Cu₉S₅/ZnO heterojunction with suitable interfacial oxygen vacancy concentration was synthesized by hydrothermal synthesis in high temperature and high pressure reaction kettle.In the reaction system with 10 mg PMS and visible light,the catalyst can degrade 20 mg·L^-1 bisphenol A more than 60%in 180 min.Characterization and experimental results show that Cu₉S₅ with higher work function acts as an electron acceptor to extract photogenerated electrons from ZnO under light,forming a Schottky heterojunction between the two,thus achieving effective separation of photogenerated electrons and holes in space.Finally,a Cu₉S₅/ZnO Schottky heterojunction with an appropriate concentration of interfacial oxygen vacancy was proposed,under the action of interfacial oxygen vacancy domain,the PMS could be decomposed controllably in the whole photocatalytic process,and a series of reactive oxygen species were generated to degrade pollutants.